Secure game download

ABSTRACT

A method for gaming terminals, gaming kiosks and lottery terminals to ensure that the code-signing verification process of downloaded game software can be trusted. Drivers independently developed from the operating system supplier are embedded within the operating system kernel to verify that the micro-coded hardware components, the BIOS ( 808 ), the operating system components and the downloaded game software can be trusted.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional application of U.S. application Ser.No. 10/520,831, filed on 12 Aug. 2005, which is a application is aNational Stage Application of PCT/US2002/029927, filed on 19 Sep. 2002,which claims benefit of U.S. application Ser. No. 60/393,892, filed on 5Jul. 2002, and which applications are incorporated herein by reference.A claim of priority to all, to the extent appropriate, is made.

FIELD OF THE INVENTION

This invention relates generally to the field of casino gamingterminals, gaming kiosks and lottery gaming terminals.

DESCRIPTION OF THE RELATED ART

On-line download of updated software and new games has been performedroutinely with lottery terminals since the on-line capture of lotteryslips started to be deployed in the late 1980s. The techniques andprocedures have been refined along the years and are now considered asessential features. On the other hand, casino regulators have alwaysbeen reluctant to introduce on-line download of updated software and ofnew games for casino gaming machines. Such reluctance stems fromconcerns relative to unauthorized intrusion and malicious modificationof software code. These concerns are understandable, particularly sincethe late 1990s because of the general trend of constructing gamingterminals using standard PC hardware and PC software platforms that aresubject to assault by hackers that are well versed in the techniques fortaking advantage of the known weaknesses and flaws of such platforms.Even now with lotteries, the appeal of making use of the broadbandpublic Internet network instead of private networking is considerable,but there are indeed significant security concerns and consequently newplans are blurred with uncertainty.

Although specialized download utilities and software update utilitiessuch as Windows Installer, InstallShield and GetRight include dataintegrity verification mechanisms to ensure that the downloaded code isnot corrupted, there is no mechanism to ensure that the code has notbeen tampered with. While secure Internet software download technologiessuch as Authenticode employ powerful PKI (Public Key Infrastructure)code signing, there is no fail-proof mechanism to ensure that the codehas not been tampered with at a later stage. Once an authorized properlysigned software module has started execution, the operating system doesnot provide means to verify if the code loaded in memory has not beentampered with to execute fraudulent operations.

Although software corporations like Microsoft have lately shifted theirdevelopment focus to making their software more stable and very secure,there is always the risk that an unknown bug or a back door existssomewhere amongst the millions lines of code that would allow someone toperpetrate some form of cheat. Hidden back-doors might be mandated bythe United States' NSA (National Security Agency) to be incorporated inoperating systems to enable them to monitor terrorism and drugtrafficking. Consequently, some corrupt employees or ex-employees havinginner knowledge of these back door accesses might be tempted tofraudulently exploit such inner knowledge. Microsoft operating systemsand other modern operating systems such as Linux are too complex andconstantly changing to consider comprehensive certification by labstraditionally trusted by game regulators for certifying gaming productsmade by gaming equipment vendors.

Moreover, using strong PKI code signing techniques does not guarantythat the code can be trusted once verified because the “verifying” tool,or the tool that verifies the verifying tool (and so on . . . ) mayitself not be trusted.

The approach of the Trusted Computing Platform Alliance (TCPA), whosespecification was finalized in January 2001, calls for the creation of aTrusted Platform Module (TPM) that requires a discrete cryptographicprocessor residing on the PC's motherboard that contains a uniquedigital signature. Microsoft's security initiative code named“Palladium”, on the other hand, uses new forthcoming hardware securityfeatures built directly into microprocessors and supporting chipsetsbeing designed by Intel, AMD and National in order to run some form oflow-level encryption, and it can also use a TPM-like module foradditional encryption. Microprocessors and supporting chipsets thatimplement Palladium may support a trusted execution mode that allowscryptographically authenticated programs access to a separate memoryarea. Such microprocessors may be equipped with a security coprocessor,which stores a unique pair of cryptographic keys in a non-volatilememory. Such a microprocessor and coprocessor may then be combined tocreate a motherboard that implements Palladium functionality. Acorresponding software component, called the Trusted Operating Root,works in conjunction with the microprocessor and its coprocessor. TheTrusted Operating Root running on the microprocessor and the coprocessorare configured to encrypt data in such a way that no other combinationof Trusted Operating Root and coprocessor would be able to decrypt it.

The above security technologies are indeed promising but they requirespecific hardware that may take several years to be proven and tojustify using them in gaming terminals. Furthermore, there may alwayspersist a lingering distrust of such large corporate software providerssuch as, for example, Microsoft. Consequently, game regulators tend tohold back the deployment of such technologies, thereby discouraging theearly adoption of networked multimedia software technologies as appliedto the heavily regulated gaming industry.

SUMMARY OF THE INVENTION

There is no better alternative for casinos and lotteries gaming computerhardware but to adopt standard PC hardware controlled by the latestgeneration multimedia software from Microsoft, QNX, WindRiver Systems,Unix or from the Linux community. It is, therefore, an object of thisinvention to provide additional security mechanisms that can performindependent and trusted verification of the Commercial-Off-The-Shelf(COTS) software installed on the gaming terminals that can be trustedbecause of its precisely defined objectives and the availability ofsource code for peer review and certification by gaming certificationlabs.

Gaming terminals, gaming kiosks and lottery terminals are hereaftercollectively referenced as gaming machines, for ease of reference.

The most promising approach available today in a COTS multimedia productthat offers comprehensive security for preventing unauthorized code fromexecuting, is integrated in Microsoft Windows XP, Windows 2000 andWindows NET. There are three technologies that address three differentlayers; namely, (1) Driver Signing, (2) Windows File Protection and (3)Software Restriction Policies. These three technologies cover all buttwo aspects of possible execution by unauthorized modified softwarecode, that is, (1) by modification of the motherboard BIOS or otheradd-on boards such as a graphic card with on-board BIOS or a SCSIcontroller with dedicated on-board BIOS, (2) by modification of anemulated CPU such as downloadable microcode for the Transmetamicroprocessor that emulates Intel CPU instructions. The risk with theemulated CPU instructions can be simply avoided by not allowing the useof such emulating microprocessors. It is, therefore, another object ofthis invention to provide a trusted mechanism to verify that themotherboard BIOS and add-on BIOS are not unauthorized. It is a furtherobject of this invention to provide a trusted mechanism to verify memorycontent, hardware register content and any form of data storage media.Verification, according to embodiments of the present invention, relieson a hash signature or on code signing with a trusted certificate.

It is to be noted that the present invention covers the prevention ofexecution of unauthorized software but not the authentication of usersand processes that are handled by the standard Access Control List (ACL)of the operating system.

According to one embodiment thereof, the present invention is a methodfor a gaming terminal to authorize execution of downloaded software,comprising the steps of running in the gaming machine a version ofMicrosoft Windows operating system having Software Restriction Policycapability, and setting the Software Restriction Policy to authorizeexecution of software code-signed with a certificate from a designatedtrusted party.

The running step may run a version of Microsoft Windows operating systemhaving System File Protection capability. The running step may run aversion of Microsoft Windows operating system having Driver Signingcapability. The method may further include the step of setting theMicrosoft Driver Signing policy to only authorize execution of driverscode-signed with a certificate from Microsoft. A step of setting theMicrosoft Driver Signing policy to only authorize execution of driversthat are code-signed with a certificate from at least one of Microsoftand a designated trusted party may also be carried out. The running stepmay run a version of Microsoft Windows operating system having SystemFile Protection and Driver Signing capabilities. The gaming machine mayinclude a microprocessor and the microprocessor and the operating systemin the running step may collectively implement Microsoft's Palladium (oran equivalent) functionality. The operating system in the running stepmay be a Microsoft Windows operating system that, together with themicroprocessor, implements Microsoft's Palladium, Windows FileProtection and Driver Signing capabilities or like functionalities. Thegaming machine may include a motherboard and the operating system in therunning step may be a version of Microsoft Windows operating systemthat, together with the motherboard, implements capabilities specifiedby the Trusted Computing Platform Alliance (TCPA) or similarfunctionalities. The gaming machine may include a microprocessor and theoperating system in the running step may be a version of MicrosoftWindows operating system that, together with the microprocessor,implements TCPA, System File Protection or Windows File Protection andDriver Signing.

According to another embodiment thereof, the present invention is also amethod for a gaming terminal to authorize execution of downloadedsoftware, comprising the steps of: running an operating system that mayinclude a configurable functionality for restricting code execution tocode that has been signed by a designated trusted party, and configuringthe restricting functionality to only authorize execution of softwarethat is code-signed with a certificate from the designated trustedparty.

The restricting functionality may conform to the Microsoft SoftwareRestriction Policy, for example. The operating system in the runningstep may be configured to prevent a replacement of selected monitored orprotected system files with files that do not originate from a trustedsource. The trusted source may be the same as the designated trustedparty. The operating system may include Microsoft's System FileProtection (SFP) or Microsoft's Windows File Protection (WFP), forexample. The operating system in the running step may be configured toonly allow execution of drivers that have been code-signed with acertificate from a trusted source. The operating system may includeMicrosoft's Driver Signing and the trusted source may be Microsoft. Theoperating system in the running step may be configured to prevent areplacement of selected monitored or protected system files with filesthat do not originate from a trusted source, and only allow execution ofdrivers that have been code-signed with a certificate from the trustedsource, such as, for example, Microsoft. The operating system in therunning step may incorporate Microsoft's Driver Signing and for example.The gaming machine may include a microprocessor and supporting chipsetsthat, together with the operating system in the running step, implementsa Palladium-like capability. The machine may include a microprocessorand supporting chipsets that, together with the operating system in therunning step, implements a. Palladium-like, System File Protection andDriver Signing capabilities. The gaming machine may include amotherboard that, together with the operating system in the runningstep, implements capabilities specified by the Trusted ComputingPlatform Alliance (TCPA). The gaming machine may include amicroprocessor that, together with the operating system in the runningstep, implements TCPA, and Microsoft's Windows File Protection andDriver Signing.

According to still another embodiment thereof, the present invention mayalso be viewed as a method for operating a gaming machine, comprisingthe steps of running an operating system loaded in the gaming machine;downloading at least one software module into the gaming machine;checking a code signature of at least one downloaded software moduleusing a trusted verification driver, and authorizing execution of thedownloaded software module in the gaming machine only if the downloadedsoftware module may be successfully verified by the trusted verificationdriver.

The running step may run an operating system that is configured toprevent the replacement of selected monitored or protected system fileswithin the gaming machine with files that do not originate from atrusted source. The running step may run an operating system that mayinclude Microsoft's System File Protection (SFP) or Microsoft's WindowsFile Protection (WFP). The operating system in the running step maycauses the authorizing step to authorize execution of the downloadedsoftware module only if the downloaded software module has beencode-signed with a certificate from a trusted source. The timing stepmay run an operating system that may include Microsoft's Driver Signingand the trusted source may be Microsoft. The downloaded software modulemay include a driver and the method further may include the step ofsetting a Microsoft Driver Signing policy to cause the authorizing stepto only authorize execution of drivers that are code-signed with acertificate from Microsoft. The method may further include the step ofsetting a Microsoft Driver Signing policy to cause the authorizing stepto only authorize execution of drivers that are code-signed with acertificate from Microsoft and/or a designated trusted source. Theoperating system in the running step may be a Microsoft Windowsoperating system that includes System File Protection and/or DriverSigning capabilities. The gaming machine may include a microprocessorthat, together with the operating system in the running step, implementsMicrosoft's Palladium capability or similar capabilities from othervendors. The gaming machine may include a microprocessor that, togetherwith the operating system in the running step, implements Microsoft'sPalladium, Windows File Protection and/or Driver Signing capabilities,for example. The gaming machine may include a motherboard that, togetherwith the operating system in the running step, implements capabilitiesspecified by the Trusted Computing Platform Alliance (TCPA). Theoperating system in the running step may be a Microsoft operatingsystem, for example. The operating system in the running step may be aMicrosoft operating system implementing TCPA, System File Protection orWindows File Protection and/or Driver Signing, for example. Theoperating system in the running step may include the Microsoft SoftwareRestriction Policy or a similar functionality from another vendor.

The present invention may also be viewed as a method for verifyinggaming terminal software, comprising the steps of installing at leastone driver into the gaming machine; taking complete control of thegaming machine with the at least one driver; verifying a legitimacy ofall software and memory content in the gaming machine; relinquishingcontrol of the gaming machine, and authorizing the gaming machine toexecute only of the software that may be successfully verified. Theverification step may include a challenge-response step to ensure thatthe trusted verifier driver has not been spoofed and/or that the trustedverifier driver is executing.

The driver(s) may be configured to execute at the highest machinepermission level. The taking step may include a step of freezing anoperation of the operating system of the gaming machine. The taking stepmay also include a step of disabling interrupts on the gaming machine.The verifying step may include verifying a BIOS of a motherboard of thegaming machine. The verifying step may include verifying a BIOS of anyadd-on board within the gaming machine. The verifying step may includeverifying ROM shadowing within the gaming machine, verifying hardwareregisters, verifying a signature in memory of the at least one driver,verify the content of files on disk within the gaming machine and/orverifying the downloadable micro-code of smart hardware within thegaming machine, for example. The method may further include a step ofauditing the source code of the driver(s) by a third party. The sourcecode of the driver(s) may also be audited by a game certification lab.The method may further include a step of certifying the driver(s) by agame certification lab and/or by a third party. The gaming machine maybe controlled by a PC, the driver(s) may be code signed and theinstalling step may be triggered by one or more plug-and-play donglesinserted in one or more ports of the PC. The driver(s) installed in theinstalling step may be code-signed by Microsoft's WHQL—or anothercertifying agency, for example. The verifying step may verify thelegitimacy of the software and memory contents without modifying thecontent thereof and the method further may include a step of reportingan outcome of the verifying step. The gaming machine further may includea third party dongle installed therein and the driver(s) may be linkedto the third party dongle to enable the third party to audit thedriver(s). The gaming machine further may include a hard disk drive thatmay include a partition formatted for simple file access (by means of aFAT, for example) and wherein the method further may include a step ofaccessing code-signed downloaded software from the simple file accesspartitioned hard disk drive. The hard disk drive partition may beformatted according to FAT2 protocol, for example. The verifying stepmay verify the memory content stored on one or more of the followingwithin the gaming machine: a hard disk drive of the gaming machine, anoptical memory of the gaming machine, flash memory of the gamingmachine, non-volatile RAM memory of the gaming machine, ferromagneticmemory of the gaming machine, magnetic memory of the gaining machine,and/or holographic memory of the gaming machine, for example.

The present invention, according to another embodiment thereof may beseen as a gaming machine, comprising: at least one processor; at leastone data storage device; a plurality of processes spawned by the atleast one processor, the processes including processing logic forcarrying out steps of: running an operating system loaded in the gamingmachine; downloading at least one software module into the gamingmachine; checking a code signature of at least one downloaded softwaremodule using a trusted verification driver, and authorizing execution ofthe downloaded software module in the gaming machine only if thedownloaded software module may be successfully verified by the trustedverification driver.

The present invention is also a gaming machine, comprising: at least oneprocessor; at least one data storage device; a plurality of processesspawned by the at least one processor, the processes includingprocessing logic for carrying out steps of: installing at least onedriver into the gaming machine; taking complete control of the gamingmachine with the at least one driver; verifying a legitimacy of allsoftware and memory content in the gaming machine; relinquishing controlof the gaming machine, and authorizing the gaming machine to executeonly of the software that may be successfully verified.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 illustrates a new game deployment cycle.

FIG. 2 illustrates a conventional code signing process.

FIG. 3 illustrates a conventional code verification process.

FIG. 4 illustrates an aspect of the present invention, in which the codesignature verification platform is itself verified.

FIG. 5 shows simplified layered view of the Microsoft security model.

FIG. 6 illustrates proposed Microsoft Palladium technology.

FIG. 7 shows a trusted mechanism for verifying the code signing ofdownloaded game software in a gaming machine, according to an embodimentof the present invention.

FIG. 8 shows a first method for trusted verification according to anembodiment of the invention.

FIG. 9 shows second method for trusted verification, according toanother embodiment of the present invention.

FIG. 10 shows a third method for trusted verification, according to yetanother embodiment of the present invention.

FIG. 11 shows an embodiment of the invention using the Microsoft WindowsHardware Quality Lab (WHQL) scheme.

FIG. 12 shows an embodiment of the invention using the Microsoft DriverSigning scheme.

FIG. 13 shows an embodiment of the present invention that uses a diskpartitioning scheme.

FIG. 14 shows an embodiment of the invention that uses a plug-and-playdongle for the activation of the trusted driver.

FIG. 15 shows a challenge response sequence according to an embodimentof the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the construction and operationof preferred implementations of the present invention illustrated in theaccompanying drawings. The following description of the preferredimplementations of the present invention is only exemplary of theinvention. The present invention is not limited to theseimplementations, but may be realized by other implementations.

A new game deployment campaign whereby one or a plurality of gamingmachines are to receive a new game is represented in FIG. 1. Theflowchart 100 starts at 102 when the decision to initiate a project todevelop and release a new game is made. The game developer 106 developsa new game application 104 whose code must be certified at 108 by arecognized certification lab 110. The certified code must then be signed112 by a trusted party 114 that is registered with a certificate issuingauthority (CA) 116. The trusted party 114 may be the certification lab110. The signed code is stored in a library 118 on a server on a gameoperator's central system 120.

When the decision to deploy the new game 122 is taken by the gameoperator, the game terminal(s) enter into a remote download session ofthe code stored in the library 124 located in the game operator'scentral system 120. Prior to downloading, the code stored in the librarymay be verified for proper code signing to ensure the code has not beenreplaced in the library. Upon receiving the downloaded code, the gamingmachine or terminal 126 executes a program to verify the code signatureof the downloaded code, as shown at 128. If the downloaded code cannotbe trusted, the code is trashed or quarantined as shown at 130, 132. Ifthe downloaded code can be trusted (successfully passes theverification), it is stored locally in persistent memory in the gamingmachine, as shown at 130, 134. Persistent memory may include, forexample, a hard disk, an optical disk, a flash memory,One-Time-Programming (OTP) memory, a magnetic memory, a holographicmemory and a battery backed-up RAM.

When the new game is requested to execute the downloaded code, thestored signed code is retrieved at 138 and its code signature isverified. If the retrieved downloaded code cannot be trusted, the codeis trashed or quarantined as shown at 142, 144. If the retrieveddownloaded code can be trusted, it is executed at 142, 146.

As noted by Eric Fleishman in Code Signing, The Internet ProtocolJournal, Volume 5, Number 1, March 2002, code signing is a mechanism tosign executable content. The phrase “executable content” refers topresenting executable programs in a manner so that they could be runlocally-regardless of whether the executable file originated locally orremotely. Code signing is commonly used to identify authorship ofapplications distributed via the Internet. Device drivers can be codesigned to inform an operating system of the authorship of that driver.For example, the device drivers for Windows 98/ME/2K/XP operatingsystems should preferentially be certified by Microsoft's device drivercertification laboratory. The entity signs the device driver executablein order to certify that the device driver in question has indeed beensuccessfully demonstrated by a Microsoft certification laboratory tocorrectly run on that operating system. Code signing may be applied toother type of files; for example Microsoft CAB files. Code signingprovides only authenticity and integrity for electronic executable filesand some other data files—it does not provide user/process privacy,authentication, or authorization.

A signature provides authenticity by assuring users as to where the codecame from and who really signed it. If the certificate originated from atrusted third-party Certificate Authority (CA), then the certificateembedded in the digital signature as part of the code-signing processprovides the assurance that the CA has certified that the code signer iswho he or she claims to be Integrity occurs by using a signed hashfunction as evidence that the resulting code has not been tampered withsince it was signed.

Code signing appends a digital signature to the executable code itselfThis digital signature provides enough information to authenticate thesigner as well as to ensure that the code has not been subsequentlymodified.

Code signing is an application within a PKI system. A PKI is adistributed infrastructure that supports the distribution and managementof public keys and digital certificates. A digital certificate is asigned assertion (via a digital signature) by a trusted third party,known as the Certificate Authority (CA), which correlates a public keyto some other piece of information, such as the name of the legitimateholder of the private key associated with that public key. The bindingof this information then is used to establish the identity of thatindividual. All system participants can verify the name-key bindingcoupling of any presented certificate by merely applying the public keyof the CA to verify the CA digital signature. This verification processoccurs without involving the CA.

A public key refers to the fact that the cryptographic underpinnings ofPKI systems rely upon asymmetric ciphers that use two related butdifferent keys, a public key, which is generally known, and a privatekey, which should be known only by the legitimate holder of the publickey.

The certificates used to sign code can be obtained in two ways: They areeither created by the code signers themselves by using one of thecode-signing toolkits or obtained from a CA. The signed code itselfreveals the certificate origin, clearly indicating which alternative wasused. The preference of code-signing systems (and of the users of signedcode) is that the certificates come from a CA, and CAs, to earn the feethey charge for issuing certificates, are expected to perform “duediligence” to establish and verify the identity of the individual orinstitution identified by the certificate. As such, the CA stands behind(validates) the digital certificate, certifying that it was indeedissued only to the individual (or group) identified by the certificateand that the identity of that individual (or group) has been verified asstated. The CA then digitally signs the certificate in order to formallybind this verified identity with a given private and public key pair,which is logically contained within the certificate itself. This keypair will subsequently be used in the code-signing process.

Code signing may be accomplished as shown in FIG. 2. The signing utilityuses a hash algorithm 212 on the executable code 202,210 to compute adigest 216 (which is also known as a one-way hash) by securelycompressing executable code 202 of arbitrary length into a fixed-lengthdigest result 216. The most common hash function algorithms used in codesigning are the Secure Hash Algorithm (SHA), Message Digest Algorithm 4(MD4), or MD5. The resulting length of the digest is a function of thehash function algorithm, but a common digest length is 128 bits. Thedigest 216, 218 is then encrypted 220 using the trustee's private key222, 224. The encrypted digest 226,228 and the trustee's digitalcertificate 230, 232, 234 are then appended to the executable code202,204, 208 to form the signed code 206. The certificate 230, 234contains the trustee's public key 231.

The private key is kept in a secure place by the trustee to prevent codesigning of fraudulent code by an unknown party.

Code-signing verification is accomplished as shown in FIG. 3.Verification of the signed code 302 may be done for example when thegaming machine retrieve the stored game code before executing it 140 asshown in FIG. 1. The verification software inspects the signed code 302to verify the authenticity and integrity of the received executable code310. The verification is done in the following manner.

-   1. Step 1 (308): The certificate 304 is examined 306, 308 to verify    that it is recognizable as a correctly formatted certificate, that    it originates from a trusted party (the trustee) and that it also    contains 309 a correctly formatted public key 336 of the trustee. If    not, the process fails.-   2. Step 2 (318): If it is, the certificate 304 identifies the hash    function algorithm 212 that was used to create the signed digest 216    within the received signed code 206, 302. With this information, the    same hash algorithm code 320 that was used to create the original    digest 216 is then applied to the received executable code 310, 312,    314, creating a digest value 322, 324, which then is temporarily    stored.-   3. Step 3 (338): The digital signature 326 (or encrypted digest    value) is then taken 328,330 from the signed code 302 and decrypted    332, 334 with the code signer's (the trustee's) public key 336    (public key is contained in certificate 304, 308, 309), revealing    the digest value 342, 344, which was originally computed 216 by the    trustee signing the code with its private key 222. Failure to    successfully decrypt this signed digest value 326 indicates that the    code signer's private key was not used to create the received    signature. If this is the case, then that signature is a fraud and    the code-signing verification process fails.-   4. Step 4 (346): The recomputed digest 324 of Step 2 is then    compared 348 to the received digest 326 that was decrypted 344 in    Step 3. If these two values are not identical, then the code has    subsequently been modified in some way and the code-signing    verification process fails. If the digests 324 and 344 are    identical, then the identity of the code signer (the trustee) is    established.

There is a dilemma in the code-signing verification process 300,however, in that the process itself might be a fraudulent verificationprocess. Consequently, it is a necessary to be able to verify that theverification platform can be trusted. The code verification processes128 and 140 may advantageously be replaced by the process according tothe present invention, as shown in FIG. 4. The code signing verification400 starts at 402 by verifying that the code-signing verificationplatform can be trusted, as shown at 404, 410. If not, then an alert 408is raised and the overall process fails. If trust can be established asshown at 410, then the code-signing verification can be safely executed,as indicated at 412. If the code-signing verification detects an anomalyas shown at 414, 416, then an alert 418 is raised and the overallprocess fails. If the code-signing verification succeeds at 420, thenthe process returns 422 to the main flow 100 as shown in FIG. 1.

Then, again, can we trust that the verification process that verifiesthat the code signing verification platform can be trusted?Consequently, according to the present invention, all the iterativeinner levels of verification processes must be examined until the lowestpossible level where trust cannot reasonably be compromised.

A simplified layered view of the Microsoft security model can beexamined on the diagram shown at 500 in FIG. 5. The computer hardware502 is controlled directly via the motherboard BIOS 504, the add-on cardBIOS 506, the Hardware Abstraction Layer (HAL) 512 and the DirectX 516services. The motherboard BIOS 504 has interfaces with the drivers 508and the HAL 512. The operating system kernel 510 has interfaces with thedrivers 508 and the HAL 512 on the lower side, and to the OS services514 on the upper side. The gaming applications 518 reside on top of theOS services 514.

The Software Restriction Policies technology 524 ensures that only codesigned by trusted parties can execute. The code forming the SoftwareRestriction Policies platform is embedded within the operating systemand it can be trusted to execute because the Windows File Protectiontechnology 522 ensures that the code is unmodified.

Equivalent technology to Microsoft “Software Restriction Policies” mayexist in other existing of forthcoming operating systems. Suchtechnologies are generically referred to herein as “Software RestrictionPolicies” regardless of the operating system supplier (e.g., Microsoft).

Microsoft's “Software Restriction Policies” support the following fourways to identify software: (1) Hash—A cryptographic fingerprint of thefile. (2) Certificate—A software publisher certificate used to digitallysign a file. (3) Path—The local or universal naming convention (UNC)path of where the file is stored. (4) Zone—Internet Zone

As stated by John Lambert of Microsoft Corporation in “Using SoftwareRestriction Policies in Windows XP and Windows .NET Server to ProtectAgainst Unauthorized Software”, January 2002, A hash rule is acryptographic fingerprint that uniquely identifies a file regardless ofwhere it is accessed or what it is named.

A certificate rule specifies a code-signing associated with acertificate for software developed or certified by trusted parties.Certificates used in a certificate rule can be issued from a commercialcertificate authority (CA) such as VeriSign, a Windows 2000/Windows NETServer PKI, or a self-signed certificate. A certificate rule is a strongway to identify software because it uses signed hashes contained in thesignature of the signed file to match files regardless of name orlocation.

A path rule can specify a folder or fully qualified path to a program.When a path rule specifies a folder, it matches any program contained inthat folder and any programs contained in subfolders. Both local and UNCpaths are supported.

Zone Rule. A rule can identify software from the Internet Explorer zonefrom which it is downloaded. These zones are: Internet, Intranet,Restricted Sites, Trusted Sites, My Computer. Currently this applies toonly Windows Installer (*.MSI) packages. It does not apply to softwaredownloaded in Internet Explorer.

Windows File Protection technology (WFP) protects system files byrunning in the background and detecting attempts to replace protectedsystem files. WFP is triggered after it receives a directory changenotification on a file in a protected directory. Once this notificationis received, WFP determines which file was changed. If the file isprotected, WFP looks up the file signature in a catalog file todetermine if the new file is the correct Microsoft version. If it isnot, the operating system replaces the file with the correct versionfrom the dllcache directory or the distribution media.

Equivalent technology to Microsoft “Windows File Protection” technologymay exist in other existing of forthcoming operating systems. Suchtechnologies are generically referred to herein as “Systems FileProtection” regardless of the operating system supplier (e.g.,Microsoft).

WFP serves the goal of maintaining a stable, reliable and secureoperating system by preventing replacement of certain monitored systemfiles except by trusted sources, such as service pack installations orWindows Update.

After detecting the replacement of a protected file, WFP searches forthe replaced files in the following order: (1) Search the dllcachedirectory. (2) If the system was installed via network install, searchthe network install path. (3) Search on the CD. In the context of thegaming machine, only (1) and (2) would be applicable.

WFP uses Driver Signing to verify files. The code forming the WindowsFile Protection (WFP) or System Protection File (SFP) platform isembedded within the operating system inner layers and it can be trustedbecause the Driver Signing technology 520 guards against unknown driversthat may introduce fraudulent code.

As stated in “Digital Signature Benefits for Windows Users”, Copyright.COPYRGT. 2001 Microsoft Corporation, Driver Signing serves the goal ofmaintaining a stable reliable and secure operating system. A driver'sdigital signature allows the system to ensure that the driver filesbeing installed have not been modified since the files passed testing byMicrosoft Windows Hardware Quality Lab (WHQL). Depending on the DriverSigning policy in effect on a user's system, the user might be allowedto disregard warnings and install an unsigned driver.

Equivalent technology to Microsoft “Driver Signing” technology and WHQLscheme may exist in other existing of forthcoming operating systems.Such technologies are generically referred to herein as “Driver Signing”regardless of the operating system supplier (e.g., Microsoft).

It is however easy to recognize that a gap exists between theabove-described Driver Signing technology and deeper levels, which mayallow fraudulent code to run. For example, fraudulent code may beintroduced in the motherboard BIOS or the add-on board BIOS. In a samemanner, fraudulent code may be introduced in micro-coded hardwarewherein micro-code is changeable. None of the Microsoft technologiesdescribed above would protect against such intrusions.

Microsoft has recently announced (June 2002) a technology code-named“alladium” that addresses the concerns raised in the previous paragraph.

Microsoft Palladium technology may be viewed at 600 in FIG. 6. Palladiumrequires that a forthcoming specially designed microprocessor (by AMD,Intel, or other CPU manufacturer) and supporting chipsets be mounted inthe computer hardware 602 in which special hardwired or downloadablesecure micro-code and security devices are incorporated 628. Inparticular, a tamper-resistant secure cryptographic co-processor isrequired but it is not clear at this stage if it would be buried insidethe microprocessor, inside the chipsets or if it would be a separatecomponent. Secure RAM memory may also be required. It is anticipatedthat any of these configurations may be supported by Palladium.

Palladium's changes to the CPU Would allow it to be placed into a newmode where certain areas of memory are restricted via a technique called“code curtaining” to an ultra-privileged piece of code called the “nub”or “TOR”. (“Nub” is the Palladium team's term for this code, and “TOR”,for “Trusted Operating Root”, is the official public term.) The nub is akind of trusted memory manager, which runs with more privilege than anoperating system kernel. The nub also manages access to thecryptographic co-processor.

It is not clear at this stage to what level Palladium extends assuggested at 632 and 633, but it is likely that this will at leastbridge the gap with the Driver Signing layer 620. The Palladium softwarecode 630 cooperates with the security devices buried within themicroprocessor and other secure devices embedded on the computer boardto provide a trusted base for everything that executes on higher levels.

The alternative approach is the Trusted Computing Platform Alliance(TCPA), whose specification was finalized in January 2001, calls for thecreation of a Trusted Platform Module (TPM) that requires a discretecryptographic processor 626 residing on the PC's motherboard 602 thatcontains a unique digital signature. Microsoft Palladium technology 630is capable of supporting the TCPA specification when a TCPA securitydevice 626 resides on the motherboard.

Although Palladium is marketed as a “Digital Right Management” (DRM)platform, it offers sophisticated advanced security technologies. Thecapability to support DRM insures that the resulting expected volume ofsales would be significant enough to justify Microsoft andmicroprocessor vendors to work together and invest development budgets.Failure to succeed will enormously benefit vendors who offer specializeddevices that guaranty DRM such as Sony DVD players and Game PlayStation.It is therefore clear that the capability to offer DRM in PCs is amatter of survival for companies such as Microsoft, Intel, AMD andNational.

Palladium enabled PCs would offer an ideal secure software and hardwareplatform for gaming terminals. However, this requires specific hardwarethat may take several years to be proven and to justify using them ingaming machines. Furthermore, there may always remain lingering distrustof large software companies and the standards they promulgate.Equivalent technology to Microsoft code-name “Palladium” technology mayexist in other existing of forthcoming operating systems. Suchtechnologies are generically referred to herein “Palladium-like”regardless of the operating system supplier (e.g., Microsoft).

TCPA enabled PCs would also offer a good hardware platform and some TCPAcompliant security devices are already available (ATMEL AT90SP0801 andEMBASSY from Wave Systems Corp). However, wide adoption by motherboardmanufacturers and availability of proven software support for Windows isnot assured.

Equivalent technology to “TCPA” technology may exist in other existingof forthcoming operating systems, security integrated circuits andmotherboards. Such technologies are generically referred to herein“TCPA-like” regardless of the operating system supplier (e.g.,Microsoft) and the hardware supplier.

Palladium is the Microsoft code-name for a secure technology thatrequires specific hardware and software applicable for PCs and othercomputer devices such as mobile phones and hand-held PC. Especially, themicroprocessor dice is adapted to incorporate deeply buried securitydevices and only special super-trusted (ultra-privileged) software modecan access to these buried devices. Although Microsoft and its partners(Intel, AMD, etc. . . . ) will make available to the public the completePalladium specification and source code, it is not clear whether thistechnology will be implemented for other operating system platform suchLinux, Unix, Wind River, QNX, etc. . . . There may be restriction issuesand patent issues that may prevent industry-wide acceptance ofPalladium. It is therefore anticipated that competing technology,although not specifically designed for DRM (Digital Right Management),may become available that addresses the same security concern, that is,to operate from a hyper-trusted based that depends on deeply buriedsecurity devices not easily accessible without very expensive equipmentmeans. For simplicity of reading, such competing technology is called“Palladium-like” hereafter.

It is, therefore, a further object of this invention to provide atrusted mechanism that does not require a special hardware securitydevice in order to verify the code-signing of the downloaded gamesoftware.

A trusted mechanism for verifying the code signing of downloaded gamesoftware in a gaming machine according to an embodiment of the presentinvention is represented in FIG. 7. The various elements shown in FIG. 7that bear the same label correspond to the identically labeled elementsin FIG. 6 and the description thereof is omitted here for the sake ofbrevity. FIG. 7 includes, however, a driver named “trusted verifier”,referenced at numeral 702. Drivers are a special class of softwarecomponents that are capable of accessing the totality of the hardwareresources 710 of the computer. When provided by third parties forcontrolling the add-on hardware that they sell that can be added to thecomputer, such as a SCSI hard disk controller and a graphics card forexample, the third party drivers (a part of 704) are notorious forcreating system instabilities and crashes. Furthermore, drivers mayintroduce fraudulent code that cannot easily be detected or protectedagainst. Fortunately, “script kiddies” that are notorious for releasingcountless variants of viruses on the Internet generally do not have thespecific knowledge required to develop new “driver viruses”. However, avery determined software developer specialized in the coding of driversmay at any time take advantage of this latent opportunity. The sameapplies to the motherboard BIOS 706 and the add-on board BIOS 708 (oneor a plurality of add-on boards and their associated BIOS), especiallyBIOS stored in Flash memory that can be downloaded from the Internet, orBIOS that is copied from slow access ROM memory to fast RAM (thistechnique is known as “ROM shadowing”). Nowadays, the BIOS for themotherboard and add-on boards, as well as the firmware for hard diskdrives, CD-ROM Writers, and other intelligent peripheral devices can beupdated, either manually or automatically, using software codedownloaded from the Internet.

Microsoft does not supply and control an entire computer hardware withall its hardware peripherals (which is called a closed platform), as SunMicrosystems and Apple do and has had an extremely tough job of makingthe operating system run reliably because of these third party provideddrivers. To resolve this issue, Microsoft has recently introduced a“Driver Signing” technology to prevent drivers of unknown origin fromexecuting and creating undesirable instabilities. The aforementionedWHQL scheme has been setup whereby third party vendors send their driverexecutable code to the WHQL that will be extensively subjected toadvanced code profiling to ensure that the code obeys a number ofspecific rules, so as to prevent it to function erratically. Uponsuccessful completion of the test and qualification, the driverexecutable code is signed with a Microsoft certificate. Consequently, ifthe operating system policy is configured to accept only Microsoftsigned drivers, the operating will prevent the execution of allnon-Microsoft signed drivers.

Although Microsoft has set up this scheme for preventing drivers ofunknown origin from executing, such Driver Signing does not guaranteethat the driver code has no latent fraudulent code in it.

A preferred embodiment of the invention takes advantage of thecapabilities of drivers (Microsoft, Linux, Unix or others operatingsystems) to let the “Trusted Verifier” driver 702 take full control ofthe computer controlling the gaming machine in order to operate securityverifications independently of the operating system and also to ensurethat the code-signing verification process can be trusted. The driversource code can be made available for peer review and for certificationby a gaming certification lab. The “Trusted Verifier” driver complieswith the rules dictated by the operating system and usually a DDK DeviceDriver Kit is made available by the operating system supplier to helpsoftware developers develop their own device drivers. A device driver orsimply driver may control a hardware device or no hardware devices. Inthe later case, the driver is commonly known as a “resident” program orpseudo driver.

In addition, the “Trusted Verifier” driver 702 may be submitted toMicrosoft WHQL in order to obtain a driver that is code-signed with aMicrosoft certificate. Consequently, the Windows operating system thatis controlling the gaming machine computer may be built with the highestsecurity allowed by the three Microsoft technologies “Driver Signing”,“Windows File Protection” and “Software Restriction Policies”.

Having the “Trusted Verifier” driver 702 signed by Microsoft WHQLensures that when the highest security policy for drivers is activated,the Trusted Verifier driver may not have been fraudulently changedsubsequent to being certified by VHQL. The verification is performedwhen the driver is loaded for execution by the Windows operating system.Microsoft WHQL may require that a specific hardware device be connectedto the PC in order for the “Trusted Verifier” to be installed and beactivated. In that case, a simple pluggable hardware device 1406 (FIG.14) such as a Universal Serial Bus (USB) dongle, a keyboard dongle, amouse dongle or a printer port dongle compliant with the Plug-And-Playstandard may be designed to allow the operating system to install the“Trusted Verifier” driver associated to hardware device.

A preferred embodiment of the invention may use a first method fortrusted verification such as depicted in FIG. 8. It is assumed that the“Trusted Driver” has been successfully installed by the operating systemas described in the previous paragraphs, either as a signed driver or asan unsigned driver, in the case of a recent version of Microsoft Windowsoperating system (standard or embedded version) or equivalent operatingsystem featuring the signed drivers technology, or a generic driver inthe case of Unix, Linux, QNX and other operating systems.

The Verify Code Signature process 128 and 140 in FIG. 1 may execute asshown in diagram 800. The method starts at 802, whereupon the TrustedVerifier driver execution is entered at 804, which gains full control ofthe computer 806. To gain full control of the computer, the driver mayrun at the highest system permission and may first disable allinterrupts to prevent preemption by high priority processes. Indeed,keeping all interrupts disabled prevents all other process fromoperating, which effectively freezes the operating system. Watchdogs mayneed to be refreshed in order to avoid a hardware restart signal orreset signal to restart the machine. Some functions may no longer beaccessible such as the hard disk, which requires the interrupts tooperate. However, some minimum access functionality may be achieved byrunning low level disk access, for example via the hard disk controllerBIOS or the hardware controller chipset (the motherboard BIOS, whosesource code can be licensed, contains all the necessary low levelroutines to access and control all the low level functions of themotherboard). Thereafter, the driver may verify the motherboard BIOS at808, add-on Card BIOS at 816 as well as verify other areas such as RAMmemory content, storage memory content and hardware registers as shownat 824, which are each compared with a trusted reference. Of particularimportance is the verification of the RAM memory areas taken by theTrusted Verifier driver itself while it is executing, in order tocompare its signature with a trusted reference to insure that no virusor other fraudulent code is attached. If any of the verification 808,816, 824 fails, as shown at 810, 818, 826, an alert is raised, as shownat 812, 820 and 828, respectively. The alert may trigger a predeterminedoperation such as flashing the red light on the gaming machine tower andpreventing further operation of the gaming machine while displaying orlogging a relevant error message. If all the verifications aresuccessful as shown at 814, 822, 830 then the driver re-enables theinterrupts at 832, and exits the Trusted Verifier Driver at 834.

The exiting 834 of the Trusted Verifier driver indicates that the lowercomponents of the software platform and of the hardware platform aretrusted and that consequently, higher level secure technologies such asDriver Signing, System File Verification and Software Restriction Policyare executing on a trusted base. Utilities, associated to SoftwareRestriction Policy and Authenticode such as “Chktrust.exe” may beexecuted to verify whether the code-signing of the downloaded software(at 836) can be trusted. If not, as shown at 838, an alert 840 maytrigger a predetermined operation such as flashing the red light on thegaming machine tower and prevents further operation of the gamingmachine while displaying or logging a relevant error message. If theverification is successful at 842, then the process is allowed to end at844.

A preferred embodiment of the invention may use a second method fortrusted verification such as depicted in FIG. 9. It is assumed that the“Trusted Driver” has been successfully installed by the operating systemas described in the previous paragraphs, either as a signed driver or asan unsigned driver in the case of a recent version of Microsoft Windowsoperating system (standard or embedded version) or equivalent operatingsystem featuring the signed drivers technology, or a generic driver inthe case of Unix, Linux, QNX and other operating systems.

While performing a game deployment cycle and downloading new gamesoftware in the gaming machines as shown in FIG. 1, the “Verify CodeSignature” process 128 and 140 is further detailed in diagram 900.

The method starts at 902, whereupon the Trusted Verifier driverexecution is entered at 904 and gains full control of the computer at906. To gain full control of the computer, the driver may run at thehighest system permission and may first disable all interrupts toprevent preemption by high priority processes. Keeping all interruptsdisabled indeed prevents all other process from operating, andconsequently the operating system is frozen. Watchdogs may need to berefreshed in order to avoid a hardware restart signal or reset signal torestart the machine. Some functions may no longer be accessible such asthe hard disk that requires the interrupts to operate. However, someminimum access functionality may be achieved by running low level diskaccess, for example via the hard disk controller BIOS or the hardwarecontroller chipset (the motherboard BIOS, whose source code can belicensed, contains all the necessary low level routines to access andcontrol all the low level functions of the motherboard). Thereafter, thedriver may verify the motherboard BIOS at 908, the add-on BIOS at 916 aswell as verify other areas such as RAM memory content, storage memorycontent and hardware registers at 924, which are each compared with atrusted reference. Of particular importance is the verification of theRAM memory areas taken by the Trusted Verifier driver itself while it isexecuting, in order to compare its signature with a trusted reference toinsure that no virus or other fraudulent code is attached. If any of theverifications at 908, 916, 924 fail at 910, 918, 926, an alert is raisedat 912, 920, 928, respectively. The alert would trigger a predeterminedoperation such as flashing the red light on the gaming machine tower andpreventing further operation of the gaming machine while displaying orlogging a relevant error message.

If all the verifications are successful at 914, 922, 930, this indicatesthat the lower components of the software platform and of the hardwareplatform are trusted and that consequently, higher-level secureverification can be trusted. A process may be executed to verify whetherthe code signing of the downloaded software at 932 can be trusted. Ifnot, as shown at 934, an alert 936 may trigger a predetermined operationsuch as flashing the red light on the gaming machine tower and preventsfurther operation of the gaming machine while displaying or logging arelevant error message, for example. If the verification is successfulat 938, then the downloaded software can be trusted. The driver may there-enable the interrupts and release full control of the computer at940. The Trusted Verifier driver may then be exited at 942 and themethod ends at 944.

Process flow 900 differs from process flow 800 in that the verificationof the code signature of the downloaded code 932 is performed within theTrusted Verifier driver and not at a higher level by the operatingsoftware. This can be seen in the diagram as process 932 is performedbefore the releasing of the full control of the computer and there-enabling of the interrupts. In order for the Trusted Verifier driverto be able to verify the code-signing of the downloaded software, thecode-signed software downloaded may have to be stored in storage memorythat allows such access from the driver. This issue is further discussedrelative to FIG. 13.

A preferred embodiment of the invention may use a third method fortrusted verification such as depicted in FIG. 10. It is assumed that the“Trusted Driver” has been successfully installed by the operating systemas described in the previous paragraphs, either as a signed driver or asan unsigned driver in the case of a recent version of Microsoft Windowsoperating system (standard or embedded version) or equivalent operatingsystem featuring the signed drivers technology, or a generic driver inthe case of Unix, Linux, QNX and other operating systems.

While performing a game deployment cycle and downloading new gamesoftware in the gaming machines as shown in FIG. 1, the “Verify CodeSignature” process 128 and 140 is further detailed in diagram 1000. Themethod begins at 1002 and the Trusted Verifier driver execution isentered at 1004, which gains full control of the computer, as shown at1006. To gain fall control of the computer, the driver may run at thehighest system permission and may first disable all interrupts toprevent preemption by high priority processes. Keeping all interruptsdisabled prevents all other process from operating, which effectivelyfreezes the operating system. Watchdogs may need to be refreshed inorder to avoid a hardware restart signal or reset signal to restart themachine. Some functions may no longer be accessible such as the harddisk that requires the interrupts to operate. However, some minimumaccess functionality may be achieved by running low level disk access,for example via the hard disk controller BIOS or the hardware controllerchipset (the motherboard BIOS, whose source code can be licensed,contains all the necessary low level routines to access and control allthe low level functions of the motherboard). The driver may then verifythe motherboard BIOS at 1008, the add-on BIOS at 1016 as well as verifyother areas such as RAM memory content, storage memory content andhardware registers 1024, which are each compared with a trustedreference. Of particular importance is the verification of the RAMmemory areas taken by the Trusted Verifier driver itself while it isexecuting, in order to compare its signature with a trusted reference toinsure that no virus or other fraudulent code is attached. If any of theverification 1008, 1016, 1024 fails at 1010, 1018, 1026, an alert israised at 1012, 1020, 1028. The alert may trigger a predeterminedoperation such as flashing the red light on the gaming machine tower andpreventing further operation of the gaming machine while displaying orlogging a relevant error message, for example.

If all the verifications are successful at 1014, 1022, 1030, thisindicates that the lower components of the software platform and of thehardware platform are trusted and that consequently, higher-level secureverification can be trusted. A process may be executed to verify whetherthe operating system components 1032 can be trusted. This may be done byaccessing the operating system files on the system storage media and byverifying their hash or code-signature with certificate against atrusted reference. Success at 1038 indicates that the operating systemcan be trusted, as no unauthorized modification has been detected.

A process may be executed to verify whether the code-signing of thedownloaded software can be trusted, as shown at 1040. If not, as shownat 1042, an alert 1044 may trigger a predetermined operation such asflashing the red light on the gaming machine tower and prevents furtheroperation of the gaming machine while displaying or logging a relevanterror message. If the verification is successful at 1046, then thedownloaded software can be trusted.

The driver may the re-enable the interrupts and release full control ofthe gaming machine's computer at 1048. Thereafter, the Trusted Verifierdriver is exited 1050 and the method ends at 1052.

The process flow 1000 differs from process flow 900 in that the TrustedVerification driver performs a verification of the operating systemcomponents 1032 against a trusted reference. In order for the TrustedVerifier driver to be able to verify the operating system components,necessary access mechanisms to the files must be available. Software toaccess files on FAT16 or FAT32 formatted disk partitions is quitecommon. Software to access files on advanced disk partitions such asMicrosoft NTFS is less common. Examples of third party products that arecapable of accessing NTFS files independently of Microsoft Windowsoperating system are Partition Magic from PowerQuest Corp.www.powerquest.com and Partition Commander from V Communications, Inc.(www.v-com.com). Source code for allowing NTFS file access is availableon the Internet from various freelance developers. In addition,Microsoft is making available the source of its operating system toselected developers.

A preferred embodiment of the invention may use Microsoft WindowsHardware Quality Lab (WHQL) scheme 1000 depicted in FIG. 11. As shown,the method starts at 1102 and the vendor or developer submits the driverexecutable code and auxiliary data to Microsoft WHQL at 1104. TheMicrosoft WHQL performs driver code analysis and testing at 1006 toverify the conformity of the driver's code with a set of rules. If thetesting 1108 fails at 1110, the software is returned to the vendor at1112, along with the test reports. If, however, the WHQL testing issuccessful as shown at 1114 then the driver is code-signed with aMicrosoft Digital Signature at 1116. The code-signed driver is sent tothe vendor/developer or alternatively is published on the Windows Updateserver at 1118 for any user connected to Internet to access through theMicrosoft Windows Update technology.

A preferred embodiment of the invention may use Microsoft Driver Signingscheme 1200 depicted in FIG. 12. In the description that follows, theDriver Signing policy 1200 is set up to accept only Microsoftcode-signed drivers. The method starts at 1202. When a new hardwaredevice is detected in the gaming machine and identified by itsPlug-and-Play identifier by the Windows operating system, thecorresponding driver is retried from storage at 1204 and itscode-signing is examined at 1206. If, at 1208, it is determined that thecode-signing is not valid or that the certificate is not from Microsoft,as shown at 1210, an alert 1212 is activating that may log the failureand abort the driver installation. If, however, the code-signing isdetermined to be valid and the certificate is from Microsoft at 1214,then the driver maybe loaded in memory at 1216 and the driver may beexecuted at 1218. Usually, when a driver is first installed, only itsinitialization strategy segment is executed. The body of the driver isexecuted subsequently when the hardware device needs to communicate withthe application. The method ends at 1220

A preferred embodiment 1300 of the invention may use a disk partitioningscheme 1302 as depicted in FIG. 13. In order to facilitate access to thedownloaded code-signed game from the Trusted Verifying driver, thedownloaded code-signed game software files may advantageously be storedin a disk partition having a simple file format such as FAT16 or EAT32.The disk 1304 may have two partitions 1306 and 1320. Partition 1306 maybe formatted in the NTFS file format, and partition 1320 may beformatted in the FAT32 file format. Partition 1306 may contain theoperating system 1310, some applications 1312 and some data files 1314.Partition 1320 may contain the downloaded code-signed game 1316 and someencrypted or signed data 1318.

It is to be noted that strong encryption of the downloaded game fileswould not present any benefit as there is not requirement to keep secretthe content of the file. The objective is to ensure that files have notbeen fraudulently modified, therefore visibility of or easy access tothe game files for reading or even writing is not a significant concern.Ease of access to files for performing code-signing audit from a trustedprocess such as the Trusted Verifier driver is highly advantageous inorder to detect fraud.

When a trusted verification process is available, it is significantlyeasier to detect fraudulent code prior to its execution than to preventsomeone from introducing fraudulent code somewhere amongst the giganticstorage disk space, by numerous means, and at unpredictable times. Oncefraudulent code has been detected, forensic analysis may eventuallyallow tracking down and prosecuting the suspect. Efficient and reliablecode-signing verification means may offer strong deterrence.

A preferred embodiment 1400 of the invention may use a plug-and-playdongle for the activation of the trusted driver as depicted in FIG. 14.FIG. 14 shows a gaming machine or device 1402 that incorporates a PC1404. Having the “Trusted Verifier” driver 702 signed by Microsoft WHQLensures that when the highest security policy for drivers is activated,the Trusted Verifier driver may not have been fraudulently changedsubsequent to being certified by WHQL. The verification is performedwhen the driver is loaded for execution by the Windows operating system.Microsoft WHQL may require that a specific hardware device 1406 beconnected to the PC 1404 that controls the gaming machine 1402 in orderfor the “Trusted Verifier” to be installed and be activated. In thatcase, a simple pluggable hardware device 1406 such as a USB dongle, akeyboard dongle, a mouse dongle or a printer port dongle compliant withthe Plug-And-Play standard may be designed to allow the operating systemto install the “Trusted Verifier” driver associated to hardware device.The pluggable hardware device may not perform any useful function apartfrom implementing a compliant Plug and Play interface, and may beconstructed using for example a low-cost PICMicro USB family 8-bitmicroprocessor from Microchip (www.Microchip.com).

To ensure that the Trusted Verifier has indeed executed and has not beenspoofed (i.e. replaced by a non authorized counterfeit program), achallenge-response controlled by the central system may advantageouslybe implemented. A challenge-and-response is a common authenticationtechnique whereby some secret information is verified in a response froma given challenge. For any of the Trusted Verifier driver scenariosdepicted of FIGS. 8, 9 and 10, an additional challenge-response step1501 may be added as shown on FIG. 15.

The Trusted Verifier driver execution is entered at 1504, which gainsfull control of the computer at 1506. To gain full control of thecomputer, the driver may run at the highest system permission and mayfirst disable all interrupts to prevent preemption by high priorityprocesses. Keeping all interrupts disabled indeed prevents all otherprocess from operating, and consequently the operating system is frozen.Watchdogs may need to be refreshed in order to avoid a hardware restartsignal or reset signal to restart the machine. Some functions may nolonger be accessible such as network communication that requires theinterrupts to operate. However, some minimum access functionality may beachieved by running low level network communication, for example via theEthernet network controller chipset (source code can be licensed thatcontains all the necessary low level routines to access and control allthe low level functions of the Ethernet network card).

A notification at 1508 may be sent by the driver via the communicationnetwork (or a special out-of-bound port) to the central server (oralternatively to an audit device) to inform that the Trusted Verifierdriver is executing. The Trusted Verifier waits until it receives areply from the central server (or alternatively the audit device) at1510 containing a challenge message produced by the central server (oralternatively the audit device). The Trusted Verifier driver computes aresponse corresponding to the challenge message according to apredetermined secret algorithm at 1512. A response, shown at 1514 issent to the central server (or alternatively to the audit device) viathe communication network (or a special out-of-bound port). After step1514, the Trusted Verifier may not engage in further dialog with thecentral server (or alternatively to the audit device) via thecommunication network (or a special out-of-bound port).

Then the driver may verify the compute platform at 1516 (motherboardBIOS, add-on BIOS, RAM memory content, storage memory content, hardwareregisters, etc. . . . ). If the compute platform verification at 1516fails, as shown at 1518, an alert is raised at step 1520. The alertwould trigger a predetermined operation such as flashing the red lighton the gaming terminal tower and preventing further operation of thegaming terminal while displaying or logging a relevant error message. Ifall the verifications are successful at 1522, then the driver re-enablesthe interrupts at 1524 and exits at 1526.

Independently upon receiving the response from the Trusted Verifierdriver at step 1514, the central server (or alternatively the auditdevice) compares the response received with the expected successfulresponse. If the received response does not match the expected response,the central server raises an alert for immediate action or for forensicanalysis. If the response matches the expected response, the event islogged for later analysis to ensure that the Trusted Verifier hasexecuted as expected, by checking for example against the activity logof games played.

Periodically, the activity log of games played is examined against thelog of Trusted Verifier responses from the associated gaming terminal.If case of a missing entry or missing entries in the log, spoofing ofthe Trusted Verifier driver may be suspected.

A special audit device may be used instead of the central system tocontrol the challenge-response authentication. The special audit devicemay be connected to the standard Ethernet port or to an out-of-boundcommunication port whereby the data traffic is not mixed with normalnetwork traffic. The out-of-bound port may be an additional Ethernetcard, a serial port, a wireless port, a USB port, a wirelesscommunication port, an Infra-Red port or any other port capable ofexchanging data.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement that is calculated to achieve the same purpose maybe substituted for the specific embodiments shown. This application isintended to cover any adaptations or variations of the presentinvention.

For example, those of ordinary skill in the art will appreciate thatvarious combination of the technologies to solve the digital rightsmanagement problem or alternatively the hyper-trusted base problem maybe derived depending on the exact computing environment. Furthermore,those of ordinary skill in the art will recognize that the invention canbe practiced on a large scale although illustrated herein with only asingle gaming terminal. For example, the gaming terminal may comprisesecure hardware processing means including multi-general-purposeprocessors (i.e. “Palladium” compliant Intel Pentium CPU) and othersecure specialized processors (i.e. graphic co-processor, networkco-processor, etc.) spanning within or in the vicinity of the gamingterminal.

The terminology used in this application with respect to is meant toinclude all hardware and software configuration and all networkedenvironments. For example, processor may mean the microprocessor (i.e.Intel Pentium), the motherboard, the computer, the processing hardware,a PC or a plurality of PCs communicating together. Moreover, theprocessing hardware is not limited to Intel x86 computer architecture(i.e. may be based on ARM or StrongARM architecture). Therefore, it ismanifestly intended that this invention is not to be limited only by thefollowing claims and equivalents thereof.

Conclusions

The invention offers a secure game download platform for updating gamingmachines software and games as well as additional security verificationat low level independently of the operating system. This way, thereluctance to trust the products of large software manufacturers such asMicrosoft may be overcome. This invention may be seen as security tool,whose source code can be audited by peers, in order to verifyMicrosoft's operating system, for example. As noted above, when atrusted verification process is available, it is significantly easier todetect fraudulent code prior to its execution than prevent someone tointroduce fraudulent code somewhere amongst the gigantic storage diskspace, by numerous means, and at unpredictable times. Once fraudulentcode has been detected, forensic analysis may eventually allow trackingdown and prosecuting the suspect. Efficient and reliable code-signingverification means may offer strong deterrence. Consequently, gameregulators that are holding back on allowing the early adoption ofnetworked multimedia software technologies may feel more comfortable inadopting such technologies.

The invention claimed is:
 1. A method for verifying gaming terminalsoftware, comprising: installing at least one driver into a gamingmachine; blocking execution of an operating system of the gamingmachine; taking complete control of the gaming machine with the at leastone driver executing at a highest machine permission level, disablinginterrupts on the gaming machine, and freezing an operation of theoperating system; verifying a legitimacy of all software and memorycontent in the gaming machine using the at least one driver, wherein achallenge-response step is used to ensure that the at least one driverhas not been spoofed and is executing; triggering an alert if theverifying operation fails; relinquishing control of the gaming machineback to the operating system; and authorizing the gaming machine toexecute software that is successfully verified.
 2. The method of claim1, wherein the taking step includes a step of disabling interrupts onthe gaming machine.
 3. The method of claim 1, wherein the verifying stepincludes verifying a downloadable microcode of smart hardware within thegaming machine.
 4. The method of claim 1, further comprising auditing asource code of the at least one driver by a third party.
 5. The methodof claim 1, further comprising certifying the at least one driver by athird party.
 6. The method of claim 1, wherein the gaming machinefurther includes a hard disk drive that includes at least one partitionformatted for simple file access and wherein the method further includesa step of accessing code-signed downloaded software from the at leastone simple file access partitioned hard disk drive.
 7. A gaming machine,comprising: at least one processor; at least one data storage device; aplurality of processes spawned by the at least one processor, theprocesses including processing logic for carrying out: installing atleast one driver into the gaming machine; taking complete control of thegaming machine with the at least one driver executing at a highestmachine permission level, disabling interrupts on the gaming machine,and freezing an operation of the operating system; blocking theoperation of an operating system of the gaming machine; verifying alegitimacy of all software and memory content in the gaming machine,wherein a challenge-response step is used to ensure that the at leastone driver has not been spoofed and is executing; triggering an alert ifthe verifying operation fails; relinquishing control of the gamingmachine back to the operating system; and authorizing the gaming machineto execute only of the software that is successfully verified.
 8. Thegaming machine of claim 7, wherein the taking step includes a step ofblocking the operation of the operating system.
 9. The gaming machine ofclaim 7, further comprising the step of auditing a source code of the atleast one driver by a third party.
 10. The gaming machine of claim 7,wherein the verifying step verifies the legitimacy of the software andmemory contents without modifying a content thereof and wherein theplurality of processes include a process to report an outcome of theverifying step.